1. Field of the Disclosure
This disclosure relates to new and improved cooking ovens, systems, oven controllers and methods concerning microwave, impingement and steam cooking separately and in various combinations.
2. Discussion of the Background Art
A cooking oven that has both convection and impingement modes is shown in U.S. Pat. No. 5,345,923 as a countertop oven with one or more removable air impingement supply structures. Each air impingement supply structure includes a specially designed food rack disposed between upper and lower corrugated impingement air forming walls. The air impingement supply structures are removably inserted into the oven's air impingement supply structure cooking chamber for operation in the impingement mode. One or more of the air impingement supply structures can be removed and replaced by a standard food rack for operation in a convection mode. The countertop oven requires n specially designed food racks for n air impingement supply structures and up to n standard food racks. The countertop oven also uses a fan disposed adjacent a side wall of the oven chamber, which increases the side-to-side footprint of the oven.
A cooking oven that has both a microwave mode and an impingement mode is shown in U.S. Pat. No. 5,254,823 as an oven that has a rather large preheated thermal reservoir (at least 60 pounds) so as to facilitate rapid heat transfer to ambient air in a plenum. However, such an oven is quite heavy and cumbersome for many applications. Moreover, the preheat time is considerable (up to two or more hours) and cooling of the oven's exterior surfaces can be difficult and energy inefficient. The oven uses impingement air from a top of the oven's cooking chamber. This will brown or crisp the top of a food product but not the sides or bottom because the browning effect of the impingement jets is lost when the impingement jets merge to form a blanket or are reflected from oven chamber surfaces. The oven has a single microwave energy feed into the bottom of the cooking chamber. This results in uneven microwave cooking as the bottom of the food product is exposed to direct microwave energy and the top of the food is exposed to indirect microwave energy. Moreover, if metal pans are used, bottom feed microwave energy results in a large amount of reflected microwave energy to the bottom feed aperture, which can considerably reduce the useful life of the magnetrons.
US Patent Publication No. 2006/0157479 discloses a combination oven which comprises an oven chamber and at least one impingement air generator disposed in the oven chamber to provide impingement air that flows substantially in a vertical direction within the oven chamber. A microwave generator is disposed to provide microwave energy into the oven chamber via at least one wall of the oven chamber. A controller operates the oven in a microwave mode, an impingement mode or a combination microwave and impingement mode. US Patent Publication No. 2006/0157479 is incorporated herein in its entirety.
Conventional accelerated cooking ovens combine some method of high speed air in combination with microwaves to cook food faster than conventional ovens. Yet there is still a need to improve food quality and to allow accelerated cooking ovens to be used in cooking a larger platform of food products. Thus, the present inventor has unexpectedly discovered that combining high speed impingement air, microwaves and steam into a single oven further increases or accelerates cooking speeds. That is, the present disclosure adds a third cooking process, such as steam, which not only increases cooking speeds, but improves the quality of some cooked food products, e.g., frozen biscuits can be processed 40% faster with better quality than conventional cooking methods.